Electron discharge device



April 8, 1941. c. F. MILLER ELECTRON DISCHARGE DEVICE Filed May 28, 1957 2 uests-Sheet 1 INVENTOR BYW ATTO R N EY April 8, 1941. c MlLLER 2,238,025

ELECTRON DISCHARGE DEVICE Filed May 28, 1957 2 Sheets-Sheet 2 .52 46 F 44 6 4/ v a .3

CM 2 W INVENTOR ATTO R N EY Patented Apr. 8, 1941 UNITED STATES PATENT OFFICE 13 Claims.

This invention relates to electron discharge devices and more particularly to improved contact bases for radio tubes and the like.

An object of the invention is to provide an improved form of contact base which can be applied either to metal envelope tubes or to glass envelope tubes.

A feature of the invention relates to an imbetween certain of the contact prongs.

Another feature relates to an improved form of outer metal enclosing envelope or shield for radio tubes of the top contact type.

A further feature relates to an improved type of composite metal-glass radio tube 'or the like.

Other features and advantages not specifically enumerated will be apparent after a consideration of the following detailed descriptions and the appended claims.

Inasmuch as the present invention is concerned primarily with the envelope, shield and base portions of a radio tube or similar device, the electrode assembly or mount portion and the particular means for supporting the same within the tube are shown merely in outline form. In the drawings,

Fig. 1 is a vertical view, partlyin section, of my improved form of shell type contact base for a glass envelope tube.

Fig. 1a is a bottom plan view of Fig. 1.

Fig. 2 is a vertical sectional view showing my improved base applied to a metal envelope tube.

Fig. 3 shows a modification of the shell base of Fig. 1.

Fig. 4 is a bottom plan view of Fig. 2.

Fig. 5 shows a glass tube with a metal outer envelope and metal locating boss, and wherein the contact prongs are directly sealed into the glass of the envelope.

Fig. 6 is a bottom plan view of Fig. 5.

Fig. 'I is a side elevational view of part of Fig. 6.

Referring to Fig. 1, the numeral I represents a glass enclosing envelope of any well-known type, having supported on the interior thereof any form of electrode assembly or mount designated generally by the numeral 2. Merely for purposes of illustration the envelope is shown as of the dome-shaped type having sealed therein a reentrant stem 3 terminating in a press 4 through which are sealed the various lead-in and support wires for the electrodes of the mount, these lead-in wires being contacted to the respective contact prongs .5, 6. While the drawing shows only two of these contact prongs it will be understood that a. greater number will be employed depending upon the number of electrodes in the mount. Thus the lead-in wires 1, 8 for the plate and grid electrodes for example, are shown connected to the prongs 5, 6. Likewise the leads 9, ID for the cathode filament or heater will be connected to similar prongs; and the lead H for the cathode sleeve will also be connected to its individual prong.

The base is in the form of a cup-shaped metal member ill the upper rim of which is adapted to engage the shouldered portion i3 of the bulb, the base being held fast in place in the customary manner by a layer ll of cement. The bottom of the cup-shaped base is provided with a series of circular openings l5, one for each of the contact prongs, it being understood that the openings ii are much larger than the outermost diameter of the contact prongs so that said prongs can project through the said openings without being short-circuited.

Preferably the contact prongs are previously staked into a circular disc it; of glass, ceramic or other insulating material and for this purpose, each prong may be in the form of a small metal tube having integrally formed circular beads I1, is to engage the upper and lower faces of the disc I 6. Integrally fastened to the center of the bottom of the metal base is a hollow tubular metal boss 19 having an integral longitudinally extending rib or key 20. The boss l9 preferably extends downwardly beyond the contact prongs so that it may cooperate with a corresponding opening in a suitable contact socket whereby the tube is prevented from being inserted into the socket in any but the correct contact relation. The glass disc IS with its contact prongs is held in place against the base of the metal shell I 2 preferably by means of struck-out tongues 2| which are bent inwardlyto firmly engage the upper face of the said disc. While the drawing shows two of these retaining lugs, it will be understood that a greater or less number may be employed. The manner of connecting the various lead-in wires to the contact prongs is wellknown in the art and detailed description thereof is not believed necessary.

The type of base described has the advantage that the contact prongs are carried as a unit by the insulator disc l6 and the boss l9 being of metal is capable of being welded to the base 25 of member l2. Furthermore the boss I9 being of metal and being interposed between the contact prongs acts to a certain extent as an electrostatic shield therebetween. In addition it may be desirable in some cases to ground the base l2 in which case the boss l9 may serve as a grounding prong to cooperate with a suitably grounded contact in the socket (not shown). While the use of bossesor keys has been proposed heretofore, they have been usually in the form of a molded insulating material and therefore are easily worn and in some cases sheared oil when the tube is forced into the correspondingly keyed socket. Furthermore these insulator bosses do not provide a conductive contacting means and being of insulation do not act as an electrostatic shield be tween the various contact prongs.

Instead of staking the contact prongs into a disc of ceramic, glass or similar insulating material, they may be molded therein. In this case the insulator disc may be of Bakelite or other suitable moldableinsulating material. Thus as indicated in Fig. 3 the prongs 5, s are'inolded into a disc 23 of "Bakelite which is also molded into the space between the contact prongs and the edge of the opening through which the contact prong passes, thus providing in effect a head or bushing of insulation in which the contact prong is supported and centered, this bushing being firmly attached to the base 25. In this embodi= ment, the boss i9 is preferably of hollow tubular metal and is welded or otherwise fastened to the disc 25 forming the bottom of cup H2.

The type of contact and keying base already described is also applicable to metal envelope tubes, as distinguished from glass envelope tubes. Thus asshown in Figs. 2 and 4, the envelope 24 is of a metal usually employed in so-called metal radio tubes, such as steel or the like. The envelope is hermetically closed by a metal header 24a which is welded to the envelope 24. Header 24a carries a plurality of metal eyelets 24b through which are sealed, by means of the glass beads 240, the various lead-in and support wires 'Il I. Preferably, although not necessarily, the header 24a is in the form of an inverted cup which is welded around its periphery to the lower end of envelope 24. The contact base may be the same as that of either Fig. 1 or Fig. 3, with the exception that the cylindrical part of the cup l2 (Fig. 1) is omitted and the radial flange 21 of the envelope 24 is welded, or brazed to the margin of the metal disc 25. Instead of joining the parts 25 and 21 by welding, the lower end of member 24 may be spun over the edge of disc 25. The insulator disc IS in this embodiment is held in place by bent over lugs 26 struck out from the disc 25 and bent back over the edge of said disc as shown in Fig. 2.

Referring to Figs. 5, 6 and 7, there is shown a composite metal-glass tube wherein the evacuated envelope proper 29 is of glass having a flattened lower end 30 into which are molded in a vacuumtight manner the contact prongs 3| to 36 inelusive. prongs 3| to 38 will be referred to as a fheader.

R that of the glass 30. Likewise if desired the flattened portion 30 of the glass envelope may be of a different composition from the remainder of the envelope in order to enable the prongs to be prop- The member 30 which carries the rigid called metal tube.

erly sealed therein. For example the glass 30 may be Corning G-12 glass, and the prongs may be of Allegheny 55 alloy, Seated against the lower end of the tube is a shallow nietal cupshaped member 31 the bottom of which is provided with three cut-out portions or windows 38, 39 and 40 and a central circular opening through which the exhaust tubulation 42 extends. As will be seen from Fig. 6 the member 31 is so disposed on the bulb 29 that the arms 43, 44, 45, form with the portion 46 a spider, with the said arms extending between adjacent contact prongs. Welded or otherwise fastened to the part 46 is a hollow tubular metal boss 41 having a flange 4| and an integral longitudinal key or rib 48.

For the purpose of electrostatically shielding the mount 49 and other parts Within the bulb 28, the latter is provided with an outer metal casing or sheath 5!! having its lower end shouldered as at 5! to accommodate the rim of member 31. The rim 52 of said member 50 is spun over against the lower face 'of member 31 and if desired may be welded thereto, although this latter is not necessary.

The arrangement of Figs. 5, 6 and 7, provides a radio tube having the advantages of the ordinary glass envelope type, with the advantages of the so- Thus the mount is substantially completely shielded electrostatically, and the parts 43, 44, 45 as Well as the metal boss 41 take part in electrostatically shielding certain of the contact prongs from each other. The contact prongs being directly sealed into the bottom of the glass envelope materially reduces the cost of manufacture of the tube.

While certain specific materials and shapes of parts have been illustrated herein it will be understood that they may be changed in many ways without avoiding the spirit and scope of the invention.

What I claim is:

1. A radio tube or the like comprising an enclosing envelope of glass having a substantially flattened bottom, a plurality, of rigid contact prongs sealed into said flattened bottom, a metal envelope within which the glass envelope is enclosed said metal envelope having a metal disclike base with a plurality of openings through which said contact prongs extend but insulated therefrom.

2. A radio tube according to claim 1 in which a metal keying boss is fastened to said metal base and extends downwardly along said contact prongs to act as an electrostatic shield therefor.

3. A radio tube including an enclosing envelope of glass having a plurality of rigid contacts directly sealed into the lower end thereof, a metal envelope within which the glass envelope is enclosed, a metal cup-like member fastened to the bottom of said metal envelope said member having a plurality of openings through which said contact prongs extend.

4. A radio tube according to claim 3 in which a hollow metal boss is fastened centrally to said cup-like member to act as a guiding key for insertion of the tube in a socket and also as an electrostatic shield between certain of said prongs. 5. A base for a radio tube of the type having a glass enclosing envelope with a flattened glass header at the lower end thereof and with a downwardly depending exhaust tubulation, said base comprising a metal cup having a central opening in registry with said exhaust tubulation, a plurality of other openings around said central opening to receive a plurality of contact prongs,

and a downwardly projecting hollow metal boss.

conductively fastened to the bottom of said cup and closing oil said central opening, said boss serving as a guiding key and as an electrostatic shield between certain of said prongs.

6. A radio tube comprising a glass enclosing envelope consisting of a bulb portion sealed in a vacuum-tight manner to a cup-like glass base, a plurality of rigid metal prongs sealed directly into the bottom of said cup-like base, a cup-like metal member within which said cup-like base is seated said member being fastened to said envelope to serve as a supporting and electrostatic shielding base therefor, and a plurality of openings in the bottom of said cup-like metal member through which said prongs insulatingly pass.

7. A radio tube comprising a glass enclosing envelope consisting of a bulb portion sealed in a vacuum-tight manner to a cup-like glass header, a plurality of rigid metal rods sealed directly into the bottom of said header and having portions extending inwardly of the envelope to act as support members and portions extending outwardly of the base to act as rigid contact prongs,

a cup-like metal supporting base fastened to said envelope and within whicl said header is seated,'

header, and a plurality of other openmember fastened to the bottom of the envelope, the bottom of said base having a plurality of ribs extending between certain of said prongs to act as an electrostatic shield therebetween and a plulatingly pass and a plurality of ribs-interposed Y between certain of said prongs, and a downwardly depending hollow metal member conductively fastened centrally to-the bottom of said cup-like 'metal member and arranged to supplement said member and ribs in electrostatically shielding certain of said prongs from each other.

11. An electron discharge device comprising a cylindrical envelope, a glass disc closing one end of said envelope, a plurality of pins arranged in a circle and sealed in said glass disc, a metal disc secured to and extending across the end of said envelope the metal disc being provided with a plurality of openings in registry with said pins,

the edges of said openings being spaced from the pins, a cylindrical metal stud extending from the center of said disc for electrostatically shielding said pins and acting as a guide for the insertion opening to receive an exhaust tubulation and a plurality of other openings surrounding said central opening to insulatingly receive rigid vcontact prongs, and an inner cup-like glass member seated in the first mentioned cup-like member and fastened thereto and having a plurality of rigid contact prongs directly sealed in the bottom thereof and insuiatingly passing through said other openings in said cup-like metal member.

said metal member having electrically connected thereto and centrally thereof a downwardly depending metal 7 member for electrostatically shielding certain'of said prongs from each other.

9. A radio tube of the type having an all-glass enclosing envelopecomprislng a glass bulb sealed to a header having a substantially flat glass bottom, a plurality of rigid metal contact prongs sealed directly through said header, said header being of a different kind of glass from said bulb whereby said prongs can be sealed therethrough in a vacuum-tight manner, and a supporting base for said tube comprising a cup-shaped metal of the tube in a suitable socket.

12. A radio tube of the type having an enclosing envelope with a flattened header of insulating material closing off the lower end thereof, said a header having a downwardly depending exhaust tubulation, a base attached to the lower end of the tube comprising a metal cup having a central opening in registry with said exhaust tubulation, a plurality of other openings around said central opening to receive a plurality of contact prongs, and .a downwardly projecting hollow metal boss on said metal cup closing off said central opening, said boss serving as a guiding key and as an electrostatic shield between certain of said prongs.

v 13. A radio tube comprising an enclosing envelope closed on at its lower end by a substantially flattened header of insulating material, a base attached to the bottom of said tube comprising an outer cup-like metal member having a central opening to receive an exhaust tubulation depending from said header and a plurality of other openings surrounding said central opening to insulatingly receive rigid contact prongs, said prongs being directly and rigidly sealed in said header and insulatingly passing through said other openings in said cup-like metal member, said metal member having electrically connected thereto and centrally thereof a downwardly depending metal member for electrostatically shielding certain of said pronss from each other.

, CARL F. MILLER. 

